"I came across these will research my recent book on the bomb, Atomic Tragedy," he tells DANGER ROOM. "They were found in a cave outside Hiroshima by a U.S. serviceman who was part of the occupation forces. We have no information about who took the photos, what became of him/her, or why the photos ended up in a cave. The serviceman held onto to them in his personal collection until 1998, when he donated them to the Hoover Archives [at Stanford University] with the provision that they not be reproduced until 2008. I included three of these photos in my book, but I wanted to make them all publicly available."